N(tau)-methylhistamine

1. N-methylhistamine:oxygen oxidoreductase (deaminating)

Catalysed by AOC2, AOC1, MAOA, MAOB and 1 morecytosolOne of 2 routes

1. histamine + S-adenosyl-L-methionine = N(tau)-methylhistamine + S-adenosyl-L-homocysteine + H(+)

Catalysed by HNMT

1. histamine + S-adenosyl-L-methionine = N(tau)-methylhistamine + S-adenosyl-L-homocysteine + H(+)
2. transport of histamine (cytosol to extracellular)

Catalysed by HNMT, SLCO1A2, SLCO1B3extracellular space, cytosolOne of 2 routes

1. histamine + S-adenosyl-L-methionine = N(tau)-methylhistamine + S-adenosyl-L-homocysteine + H(+)
2. transport of GSH and histamine (cytosol to extracellular)

Catalysed by HNMT, SLCO1A2, SLCO1B3extracellular space, cytosol

1. histamine + S-adenosyl-L-methionine = N(tau)-methylhistamine + S-adenosyl-L-homocysteine + H(+)
2. transport of histamine (cytosol to extracellular)
3. transport of S-glutathionyl-2-4-dinitrobenzene (cytosol to extracellular)

Catalysed by HNMT, SLCO1A2, SLCO1B3extracellular space, cytosolOne of 4 routes

1. histamine + S-adenosyl-L-methionine = N(tau)-methylhistamine + S-adenosyl-L-homocysteine + H(+)
2. transport of histamine (cytosol to extracellular)
3. transport of glycoursodeoxycholate (cytosol to extracellular)